The present invention relates to a self-piercing type rivet setting system, and in more particular, to a self-piercing type rivet setting system suitable to cooperate with an electrically controlled system, such as a robot or a jig, which is used when two sheets or three or more sheets of plate members (or a plate member and a part) are riveted using a self-piercing type rivet in a sheet metal assembling operation, for example, in a car body assembling operation (especially in an aluminum body assembling operation).
An exemplary self-piercing type rivet setting system has been disclosed in European Patent Specification EP 0 893 179. FIG. 2 thereof shows an exemplary self-piercing type rivet. Basically, the self-piercing type rivet is formed with a flange-like head portion and two legs extending from the head portion. When the rivet is driven by a punch and die into a workpiece to be riveted, for example, into two sheets of body panels, the legs deform at their tips to be expanded while piercing the panels thus to couple the panels with each other by the expanded leg portion and the head portion. A self-piercing type rivet is suitable for coupling of aluminum body members for which the welding cannot be made, and further, demand for a self-piercing type rivet is expected since more aluminum body members will be prospectively employed for a car body member to meet an increasing requirement for a weight reduction thereof.
Though not disclosed in the above patent document, a conventional self-piercing type rivet setting system driven by oil pressure or electric power comprises an independent rivet swaging assembly and a jig or robot as a means for moving the rivet swaging assembly to put it in position relative to a predetermined site to be riveted on a workpiece. The rivet swaging assembly is mounted on a front end of an arm of the robot or jig. Such conventional apparatus needs, in addition to the rivet swaging assembly for the self-piercing type rivet and an controller therefor, a jig or robot and another controller for controlling the jig or robot to be driven, which has made a cost of an arrangement expensive. Further, in a facility where a robot or jig moves the rivet swaging assembly to the working sites, the rivet swaging assembly has a built-in driving unit therein, so as to make its volume as a whole bulky. Yet further, an interface cable extending from the controller to the rivet swaging assembly has interfered with complexity in geometry of a car body and the like, leaving some sites unavailable to be riveted.
In accordance with the present invention, a self-piercing type rivet setting system is provided that employs a single integrated controller. The rivet setting system comprising: a rivet swaging assembly for setting a self-piercing type rivet; a first controller for controlling a riveting operation of the rivet swaging assembly; a moving means for moving the rivet swaging assembly to put it in position relative to a predetermined site to be riveted on a workpiece; a second controller for controlling an operation of the moving means; and a rivet feeder for automatically feeding a self-piercing type rivet to the rivet swaging assembly; and wherein the first controller also controls a feeding of the self-piercing type rivet from the rivet feeder; the self-piercing type rivet setting system is characterized in that the first controller is incorporated into the second controller to be formed into a single integrated controller, and the rivet swaging assembly is integrally incorporated into the moving means. It should be noted that from the integrated controller, one interface cable extends to the moving means and another interface cable to the rivet feeder.
In the self-piercing type rivet setting system described above, the moving means for moving the rivet swaging assembly may be a robot or a jig. In this case, the rivet swaging assembly may comprise: a C-shaped frame mounted on a front end of an arm of an articulated robot; a die mounted to one end of the C-shaped frame; a punch mounted to other end of the C-shaped frame, the punch opposed to the die to be capable of moving into contact with/away from the die; and a means for movably supporting the punch allowing the punch to move into contact with/away from the die, the means for movably supporting the punch comprising an electric drive motor fixedly mounted on the front end of the robot arm and a link arm coupled with the motor for moving the punch in a linear direction, which allows a mechanical structure of a riveting function portion to be made more compact.
As described above, according to the present invention, since the controller for the moving means (e.g. a robot or jig) for moving the rivet swaging assembly to put it in position relative to a predetermined site on a workpiece to be riveted, or the second controller, is incorporated with another controller for the rivet swaging assembly of the self-piercing type rivet, or the first controller, to be formed into a single integrated controller, the housing for the first controller is not necessary any more and also the interface cable between the controller for the rivet swaging assembly and the another controller for the moving means such as a robot is not necessary, though both being necessary for the conventional apparatus. Further, since, in addition to the integration of the controllers, the rivet swaging assembly is incorporated into the moving means such as a robot, the interface cable extending from the controller for the rivet swaging assembly to the rivet swaging assembly is no longer necessary, which is necessary for the conventional apparatus, and this reduces a possible interference with the workpiece to be riveted and ensures the riveting operation to be performed at a desired site. Thus, a size of the self-piercing type rivet setting system as a whole, a cost thereof and a size of the rivet swaging assembly could be reduced, and still further a number of interface cables could be reduced.